Time Swap
by FicklePencil
Summary: One day, Renet will master the Time Scepter. In the meantime, Leonardo and his family have to adapt. 2012 universe.
1. Prologue

_Author's Note: 2012 universe, takes place after Season 4. Translated from my fic "Echange temporel"._

* * *

**Prologue**

* * *

Leonardo bowed to his father's shrine. Splinter had died months ago, but it could as well have been yesterday for him. He missed him so much. They all did.

He sighed and straightened up. He was way too young to be Sensei, way too young to be responsible for an entire ninja clan - no matter how small it was.

Shredder hadn't left him any other choice.

Shaking his head, he decided that it was time to join his brothers. Their company prevented him from focusing on the past, and besides, he felt the need to enjoy a relaxing afternoon for once.

He left the dojo, instinctively bowing his head to avoid Michelangelo's skateboard, which was crossing the living room at high speed with said Michelangelo on it. Then he stepped aside to let Renet pass. The Assistant Time Master had become very close to his brother, which you wouldn't have guessed considering how furious she looked.

"Mikey! Come back at once, we're not done," she shouted, her hands grabbing the Time Scepter as if it was a club.

"I'm sorry! I'm really sorry!" Michelangelo had obviously no intent to stop, and Leonardo winced when he heard the creaking of abused furniture. Once again, the living room was going to be a mess.

Resigned, he walked to the couch where Raphael was watching the chase with the utmost interest. Leonardo sat down next to him.

"Do I want to know?"

Raphael nodded, grinning. "Mikey told her that he had never met a girl as old as she is, and that it was awesome."

"As beautiful, you mean?" Leonardo inquired.

"No, no, as old. He's probably right, mind you, but Renet took it the wrong way. That or she's very good at faking it."

Renet was running past the couch and winked at them. Leonardo shook his head.

"I see."

The distinctive sound of an explosion diverted his attention. It was coming from Donatello's lab, and Leonardo would have hurried to the room if he hadn't heard Donatello's disgusted exclamation. Nothing out of the ordinary, then; no reason to worry.

Leonardo folded his hands calmly as he heard cracks and clashes coming from the kitchen, where Renet's chase was going on. This was Michelangelo's favorite room in the lair and he would never damage it beyond repair.

A few seconds later, Michelangelo burst into the living room again, Renet after him. As they came closer to the couch, another explosion resounded, much stronger than the first. Leonardo frowned. This time, he was going to check on Donatello, and maybe veto this particular set of experiments. In one graceful move, he jumped above the couch, careful to avoid Michelangelo and Renet still running across the room…

A blinding light beam caught him mid-air. He let out a strangled cry and fell on the ground, all grace forgotten.

* * *

"Leo!" Raphael shouted, running to his brother.

Leonardo grunted and sat down, drawing his knees up to rest his head on them. Eyes closed, he massaged his head.

Raphael sighed in relief before turning to Renet, ready to jump down her throat.

"What was that?"

Renet took a careful step back. "I… uh… he surprised me, and I activated the Time Scepter. Don't worry, it wasn't set on time travels."

"We're lucky indeed." Raphael crossed his arms, not ready to be so easily soothed.

Luckily for Renet, Donatello chose this precise moment to leave his lab with his head down. His skin, which should have been a nice green, was now a bright purple. This effectively caught Raphael's attention.

"Don't ask." Donatello shook his head before noticing Leonardo on the ground. "What happened?"

Renet cleared her throat.

"The Time Scepter uses self-defense, and it's linked to its bearer's emotions. I… uh… I'm still learning the theory behind it."

"The Time Scepter can stun? Interesting," Donatello whispered.

"Don't get any ideas," Raphael grumbled.

Donatello ignored him to focus on Renet. The Assistant Time Master was apologizing to Leonardo, who was ignoring her completely. He was obviously still shell-shocked.

One of Renet's many watches rang, and she winced. "I have to go home if I don't want to be late. And believe me, I don't want to be late. Lord Simultaneous is a tyrant, I'm telling you." Shaking her head, she waved at the turtles. "See you later, Mikey! And sorry again about Leo."

"No problem, Renet!" Michelangelo's huge grin almost didn't waver when Raphael glared at him. "What?"

"That girl is a walking disaster."

"Like you're not a walking disaster." Michelangelo crossed his arms, ready to defend his friend.

On the ground, Leonardo was still stroking his head. With a last moan, he unfolded his body and stood up, looking at them. His eyes widened when he registered the state of the living room.

And his brothers froze.

"Guys, what happened? Master Splinter will be furious when he'll see that." Leonardo waved at the place, including Donatello-the-purple-turtle in his gesture.

Raphael opened his mouth, but no sound left it. Michelangelo raised his hand to hide his. Donatello lifted a finger, his questioning face showing that he wasn't sure he had heard his brother correctly.

"Master Splinter?" he said weakly.

Leonardo tilted his head.

"Well, you know. A giant rat. A ninja master. Our Sensei?"

His tone was clearly sarcastic, and Raphael let out a strangled cry, very unworthy of the powerful warrior he was. Donatello nodded, assessing the situation. Leonardo shouldn't have had this voice, the voice he had before Shredder almost killed him. He shouldn't have had this juvenile look either, without the scars their many battles had left on his skin and shell.

Granted, Renet had told them that the Time Scepter wasn't set on time travels. However, she wasn't always the most reliable person.

"Guys?" Leonardo was obviously wondering what he had said wrong. "What's the matter?"

Michelangelo took a deep breath and gave his brother a shaky smile. Raphael, still under shock, opened and closed his mouth again.

Donatello stepped forward and put a purple hand on his brother's shoulder. "Everything is fine, Leo," he said in a tone that meant the exact contrary. "By the way, how old are you?"

Leonardo smiled, a little incredulous. "I'm fifteen, of course. Like you three. Why are you asking, Donnie?"

Michelangelo was the first to break the following silence. "Well, we're almost there," he said encouragingly. "Four years aren't that big a deal, right?"

Raphael's fists clenched and unclenched convulsively. Obviously, he wasn't appreciating the joke.

"Call back Renet. Now."


	2. Confusion

**Confusion**

* * *

As Michelangelo hurried to his room in order to contact Renet with his communication orb, Leo watched Donatello and Raphael, eyes narrowed.

"Renet? Who's that?"

"She's… an old acquaintance," Donatello whispered, his tone showing very little enthusiasm. "We'll give you the details later."

Michelangelo was already coming back. He looked despondent.

"She's not answering."

Raphael threw his arms up. "Just what we needed."

Michelangelo frowned. "She's busy. She's working, not like some people I know!"

"It must be such high-quality work!" Raphael shouted. "Don't worry, it wasn't set on time travels," he quoted, deliberately taking a high-pitched tone. "Not set on time travels my a-"

Leo cleared his throat, catching his brothers' attention. "Time travels?"

"Well done, Raph." Donatello sighed. He wanted nothing more than to take a shower, but he didn't see it happening anytime soon.

Leo crossed his arms. "What's happening here?" he asked, his firm tone clearly indicating that he wasn't going to be satisfied with evasive replies.

Raphael kept silent. Everything in his sulky attitude indicated that he wouldn't answer. Donatello didn't talk either, too busy thinking about the best answer he could give to this embarrassing question. So Leo turned his focus towards Michelangelo, who bit his lip and blinked several times. Leo narrowed his eyes and Michelangelo moaned.

"So, uh… you see…"

He interrupted himself and sent a desperate look his other brothers' way.

Leo shook his head. If nobody was willing to answer him, it was time to go to a higher instance. "I'll ask Splinter."

"No!" his three brothers exclaimed in unison.

Their voices sounded extremely panicked, and Leo interpreted it as the well-founded fear that their father wasn't going to be happy with the living room's state. How could he have known that Splinter was no more?

"Then tell me what's with you," he demanded.

"Donnie, you're the explanation-lover. You tell him." Raphael waved towards Donatello, not caring about the glare said explanation-lover was giving him.

Donatello courageously opened his mouth to speak, his brain suggesting one almost plausible explanation after another - they had to tell Leo the truth or he would never leave it down, but not all the truth, there was no way they could tell him Splinter was dead - when a tiny purple turtle trotted inside the room. Breathing fire.

Leo jumped. "What is _that_?"

"Don't talk about Chompy like this," Raphael threatened him as he carefully picked up the tiny turtle.

"It's Spike 2." Michelangelo nodded. "It's an alien. His mom is a gigantic flying turtle who could destroy the Earth with a sneeze. In fact, she almost did."

Leo took a deep breath and rubbed his temples.

"Spike 2. And where is Spike 1?"

"Uh…" Michelangelo offered him a sheepish smile. "Raph mutated him into a giant battle turtle."

Leo nodded. "Sure, Mikey. Whatever you say."

"It's true!" Michelangelo protested. "Raph, tell him it's true!"

Raphael looked daggers at his brother. He didn't appreciate to be reminded of this disastrous episode of his life.

Donatello, having taken advantage of the interlude to choose the best possible explanation according to the circumstances - only 30% of probability that Leo would have a heart attack - took the plunge.

"Listen, Leo. I know this must look strange to you, but you don't have to worry. Everything is fine. It's just that… that you are…" Donatello wasn't aware of it, but his voice was becoming more and more high-pitched. "In the future."

"In the future." Leo seemed doubtful at best.

"Yes, exactly. In the future," Michelangelo and Raphael insisted.

Donatello went on, anticipating future difficulties. "And Splinter isn't there. He took April with him for her kunoichi training." He made a mental note to give April a phone call so she wouldn't pay them a visit for as long as this Leo would be there.

"Then where is Future-Me?" Leo asked, his arms still crossed but his voice slightly hesitant. He was looking at Chompy, the alien turtle, rubbing his tiny head against Raphael's cheek.

His three brothers looked at each other.

"Now that's a good question," Donatello whispered.

* * *

_Four years earlier_

Leonardo rubbed his head to soothe his violent headache and stood up. Looking at his surroundings, he immediately knew that he wasn't at the right place.

Or more precisely, he wasn't at the right time.

Granted, he was still in the lair's living room; but an old episode of _Space Heroes,_ his favorite cartoon, was on television. He must have been - that was, his past self must have been - watching it.

And he hadn't been watching it alone. His three brothers were sitting on the couch, looking at him with big eyes.

_Great. Just what I needed, _he thought.

He cleared his throat. "Hello."

"Uh, Leo?" Mikey asked. "Are you sick? Your voice is all weird."

His voice. Of course. It gave Leonardo a clue about the length of his temporal jump. He had landed before the disastrous episode when the Shredder had beaten him almost to death, sending him into a coma that had lasted three months.

"Hmm, yes. About that…"

Leonardo interrupted himself, unsure of how he could explain any of it to these younger brothers.

"Leo, what about the scars?" Raph suddenly exclaimed.

"So you're seeing them to?" Donatello nodded. "I thought I was hallucinating."

From his expression, he must be wondering how such marks could have appeared on his brother's body in a mere few seconds.

Leo swore inwardly. Another thing that wasn't going to be easy to explain.

"Listen, I…"

"Leonardo?"

Leonardo froze. He had heard that voice for the last time months ago, coming from a spirit. He turned around, his heart beating faster in his chest.

The tall figure in front of him wasn't a disembodied being, but rather a giant rat in the flesh. Leonardo called upon every fiber of highly trained ninja in him to keep his composure, but he couldn't entirely prevent his voice from shaking.

"Sensei."

* * *

_Author's Note: So we have Leo, Raphael, Michelangelo and Donatello in the present, and Leonardo, Raph, Mikey and Donnie in the past. With Splinter._

_I wonder how they're going to cope…_

_And feel free to report any mistake you see. It would be immensely helpful to me._


	3. Diversion

**Diversion**

* * *

_Past_

Leonardo was unable to move. Of course, if he was in the past, Splinter was still alive.

He breathed in and breathed out, trying to control the storm of his emotions. His father, alive… He could warn him, he could save him… He could tell him to stay away from Shredder, to not leave the lair…

Leonardo closed his eyes. And then what? Should he tell his brothers everything that was going to happen? What if he changed the future for the worst? In his present, he and his brothers were still alive. The Kraang hadn't mutated the Earth. Shredder wasn't a threat anymore… They came within a hair's breadth of failing so many times, he couldn't take the risk to alter this timeline…

He couldn't play that dangerous game.

"Leonardo?" Splinter repeated.

Leonardo opened his eyes again. Concern was mixing with surprise in his father's gaze. Splinter must have realized that something was wrong, that his son didn't look like the turtle he was supposed to be…

Without even realizing what he was doing, Leonardo flung himself into his father's arms, hugging him with all his strength.

"My son, what's the matter?" Splinter asked, hugging him back reflexively. He brushed his scars, and Leonardo felt him stiffen.

He knew that his father was going to demand an explanation, and he knew that he would be unable to lie to him. But certainly Splinter would understand that he shouldn't ask too many questions. Everything Leonardo had to do what to tell him he was coming from the future. Although Splinter might have already guessed…

"Master Splinter." Leonardo broke the hug with regret. "May I talk to you in private?"

Splinter nodded. "Of course."

Leonardo followed his father inside the dojo and knelt in front of him, like he had done a thousandth times before.

Before…

"I'm listening," Splinter told him encouragingly.

Leonardo took a deep breath.

"Well, I… I… I don't exactly know what happened, but…"

The dojo smelt like his father, a warm and reassuring scent.

"I know it's hard to believe…"

The light played with the leaves of the dojo tree, and shadows danced on the tall rat's face, giving him this expression of serenity that always soothed Leonardo…

He forced himself to carry on.

"I'm coming from the future," he whispered. "I can't tell you more, I don't want to interfere with the past… I'm here by accident, I…"

He stopped talking. He would trust his father's wisdom. If Splinter insisted on knowing, Leonardo would tell him everything… Absolutely everything…

Splinter kept quiet for a very long time.

"Are your brothers alright?" he finally asked. "That's all I need to know."

Leonardo nodded slowly, noting his father's choice of words.

Splinter closed his eyes briefly. "And Leonardo… I mean, the Leonardo you were… Is he with your brothers right now? In the future?"

"I think so. If that's the case, Raph, Donnie and Mikey will watch over him." He didn't add that Leo could as well be lost in limbo. "If I'm here, he's alright," he said instead. "My existence depends on his, after all."

Splinter looked at him carefully. "And what are you suggesting we do to set things right?"

"I… I think we should wait. I'm sure my brothers will find a solution."

_Or Renet will,_ he added in his head_. She better hurry._

* * *

_Present_

Raphael, Donatello and Michelangelo looked at Leo as if they didn't know what to do with him, which was making said turtle very uneasy.

Leo cleared his throat. "So… What are we going to do now? I would hate to bother you," he said in a somewhat sarcastic tone.

Raphael and Michelangelo turned to Donatello, their faces expressing their hope in a magic remedy only he could provide. Donatello put his hands on his hips.

"You know, I have absolutely zero idea how to build a time machine. And even if I did, I would be highly surprised if I could find the appropriate equipment inside the sewers!"

Michelangelo threw his arms around Donatello's neck, not rebuffed at all by the purple paint still covering his brother. "You're the best, Donnie," he emphasized. "You're going to make it."

"We're counting on you, really, we do," Raphael added with conviction. He did look desperate.

Donatello sighed. _Thank you so much, Renet, _he thought wryly. "Fine, I'll give it a try. After I have a shower." He walked away with heavy steps.

"I need to think," Leo whispered. "If you don't mind, I'll go meditate in the dojo."

"No!" Raphael and Michelangelo both exclaimed. Their father's shrine was in the dojo. If Leo saw it, he would understand the truth.

Leo watched them in surprise. "What's wrong?"

"Nothing's wrong," Michelangelo whispered in a voice that clearly pointed towards the exact contrary. He nodded slightly to Raphael, indicating that he was taking that particular matter in his hands, and dashed towards the dojo.

Raphael was left alone to take care of the necessary diversion. "You don't want to watch the TV instead?" he said grumpily, stroking Chompy's head for more inspiration. "I'm sure we can find a rerun of your stupid cartoon somewhere."

"And what about the living room?"

Raphael shrugged. The living room had seen worse, and they could clean it later, when things would be back to normal. That was, with each Leonardo at his right place. "No need to hurry. Like Donnie said, Splinter isn't home at the moment."

Leo nodded slowly. He was obviously suspicious, and Raphael wondered whether his brother could feel how reluctant he was to pronounce these words. How long would they be able to hide the truth from him? This Leo might be younger and less experienced than his Leonardo, he still had a formidable intuition for everything concerning his family.

Raphael's only hope - and his biggest concern - was that Leo had way too much admiration for Splinter to conceive that he could have been killed by Shredder. Raphael himself had a hard time believing it, and he had seen it with his very eyes…

They all had a hard time believing it.

Raphael shook his head wildly. He didn't want to think back. "Come on," he told Leo.

Michelangelo joined them fifteen minutes later. "Now you can meditate in the dojo all you want," he said, out of breath.

But Leo was deep into Captain's Ryan amazing adventures and he didn't even look at his brother. "Later, Mikey. I've never seen this episode!"

Raphael let out a disdainful groan. He had never understood why his brother loved this so-called hero so much, but in this case Leo's passion was very useful to them.

He had to admit, though, that it was pleasant to see Leo so smiley and relaxed, sitting on the floor in front of the TV with his arms around his knees. These days, his Leonardo rarely indulged like this.

Raphael felt the imperious need to protect Leo from the terrible truth.

He wasn't ready to know.


	4. Complication

**Complication**

* * *

_Past_

"So you're coming from our future?"

Leonardo bit his lip. Of course his brothers - or at least these younger versions of his brothers - had eavesdropped on his conversation with Splinter. It was a good thing that he hadn't talked about anything important - at least nothing that they would pick up on.

Instead, he had basked in his father's presence, trying to impress on his memory Splinter's slightest gestures, enjoying every instant he could spend in the rat's company.

"Yes," he answered. There was no need to deny the obvious.

"How's the future?" Mikey asked.

"It's… Uh…" Leonardo hesitated. Without even talking about the fact they were orphans, how could he explain with words the long way they had gone?

Raph's interference gave him a brief respite.

"Don't worry, Mikey, I'm sure you're still the same turtle. As young at heart as you're now."

"Thank you, Raph." Mikey nodded solemnly, ignoring Raph's teasing tone.

"At the very least, we must have been in epic fights." Raph was looking pointedly at Leonardo's scars, who couldn't help feeling embarrassed.

"You could say that," the older turtle mumbled.

"And, uh…"

Leonardo turned towards Donnie, who was talking for the first time and kept his eyes focused on the ground.

"Are April and I… You know… Do we…"

Leonardo watched him for a moment, trying hard not to facepalm. That was all Donnie had to say? But it was true that he was desperately in love with the teenage girl.

"Donnie, it's better if I tell you as little as possible, do you understand?" he answered delicately.

He most certainly wasn't going to tell him that April was resisting his charms, nor that Casey Jones had become a very serious rival in this matter.

By the way, had they already met Casey?

Leonardo watched the living room carefully, looking for a detail that could help him answer this question. _Hey, Raph, did you already let a human follow you to the lair? A teenager as hotheaded as you are, _he thought. For very obvious reasons, he couldn't ask this question aloud.

He didn't have to look very far. On the couch, a small green turtle was chewing on a leaf. It was a precious clue. _Spike is still here. They don't know Casey yet._

Raph nudged Donnie. "Don't spoil yourself the surprise," he teased. He grinned at Leonardo. "But now that we're talking about enamored turtles, maybe you could tell us if you've stopped falling for the enemy?"

Leonardo watched him, speechless.

Raph shook his head. "Karai, remember her? Last month, you were thinking of nothing but her."

Leonardo felt his cheeks burn. He tried to focus on the information Raph was unknowingly giving him. He found himself a few weeks after his first encounter with Karai, which meant that they hadn't fought Kraang Prime yet.

In other words, he was a lifetime ago.

"And to think that you believed she was on our side," Raph added, almost for himself. "Seriously, you're so naive."

Donnie and Mikey nodded vigorously to show their approval, and Leonardo felt offended.

_I was right. She's our sister._

Too bad he couldn't tell them that.

* * *

_Present_

Raphael snapped out of his dreams when Leo entered his room with decided steps. The young turtle had finally wanted to train in the dojo, and Raph had taken the opportunity to take a nap while Donnie was doing Donnie-only-knew-what in his lab with Mikey's more or less efficient help.

"Where are my katana?"

Raphael immediately forgot his irritation and raced to find a suitable answer. The katana Leo was talking about didn't exist anymore. They had been broken and Leonardo hadn't repaired them. Now Leonardo only used the katana which had belonged to their father, the ones he had carried during the ultimate battle against the Super Shredder; the ones he had used to end the Shredder.

Raphael couldn't imagine giving these katana to this version of Leo, way too young and immature. In a way, it would have been betraying his brother.

Besides, Leo was bound to ask some very embarrassing questions.

Raph had a stroke of genius worthy of Donatello.

"You… You were carrying them. I mean, our Leo was carrying them."

"Oh." Leo sounded disappointed. "That's too bad."

Raphael gauged him pensively. "Do you want to train together? You and I, hand-to-hand-combat. The loser does the dishes."

Leo smiled. "Deal."

Raphael jumped from his hammock, his spirits considerably lifted. He had no doubt he would win, which was good because it was supposed to be his turn to do said dishes.

And, indeed, he defeated Leo every single time. It had been a very long time since it last happened, and brought back good memories.

"Maybe next time," Raphael teased, extending his arm to help Leo stand up. "You're not that bad, but you've still a long way to go."

Leo took his offered hand, looking clearly annoyed.

Raphael grinned. "Your dishes are waiting for you. You know the way." Maybe he would stay in the kitchen's doorway and watch Leo in order to better enjoy his victory.

Unluckily for him, his perfect plan was disrupted by a human-shaped whirlwind in black and grey.

"Leo, I've been trying to join you for hours," the whirlwind exclaimed, pointing an accusative finger towards the blue-masked turtle. "Do you even look at your phone?"

"Karai!" Leo jumped backwards, looking for a weapon.

Raphael rubbed his temples. Why, why did Karai have to request their help today? She might very well be the last person Raphael wanted in Leo's vicinity right now.

Said Leo noticed that his brother hadn't moved an inch and didn't seem to consider the kunoichi as a threat, or at least not as an immediate threat.

"Uh, Raph?" he began hesitantly. "Karai is in our lair! You're not afraid that she'll try to kill us? Or tell Shredder where we are?"

Karai widened her eyes.

"Tell Shredder?" she croaked. "Are you crazy? How could I tell Shredder, you ki-"

Raphael jumped on her to press his hand against her mouth. "Karai, meet Leo-from-the-past," he hurried to say. "A-very-distant-past-and-you-better-keep-your-mouth-shut."

Karai took his arm and twisted it mercilessly to keep him away from her. She watched Leo with more attention. "Now that you're telling me, it's true he looks younger." She tilted her head, fists on her hips. "What happened this time?"

"You mean who." Raphael pulled a face. "One word: Renet."

Karai nodded as if this explained everything.

In front of them, Leo still couldn't believe his eyes. "Raph? What's happening?"

"Leo…" Raphael sighed. "Karai is our ally now."

"Then… I was right!"

Leo's triumphant tone was exasperating.

"Only in part," Raph mumbled.

Karai was grinning from ear to ear. "I'm still going to need your help, Leo," she whispered. "Do you think you could come with me?"

Leo opened his mouth and closed it, his cheeks a very interesting shade of red.

Raphael didn't let him speak.

"Are you crazy?" he yelled at Karai. "He's not going to leave the lair!"

He immediately realized that it had been the wrong thing to say. Leo was looking at him with an expression both stubborn and furious.

"I don't see why not," he retorted. "If Karai needs _my _assistance, the very least I can do is to grant her request."

_Oh come on,_ Raphael thought. _Not Leo the white knight. That's all we needed._

"You don't even have your weapons!" he exclaimed.

"It doesn't matter," Karai said. She was obviously enjoying herself immensely. "We'll go to my armory first, and I'll lend you twin katana. Let's go!"

Raphael glared daggers at her, to no avail. He took a deep breath. If Leo wasn't going to be reasonable, he, Raphael, would have to do damage control.

"I'm coming with you. Let me just tell Donnie and Mikey."

He would also take his T-Phone and a few extra weapons, just in case.

"You don't have to, Raph." Karai put a hand on Leo's shoulders, who smiled at her blissfully. "Leo and I, we can manage."

"You can manage to find trouble, no doubt." Raphael waved a threatening finger her way. "This'll only take a second. Don't you dare leave without me."

Karai gave him a smile that was supposed to look innocent, and Raphael hurried to get ready.

He really meant that it would only take a second. Karai and Leo weren't going to give him the slip in such a short time, were they?


	5. Excursion

**Excursion**

* * *

_Present_

Raphael restrained himself from shouting at the empty living room. Sure, he had taken maybe fifteen seconds instead of one - but was it really too much to ask for?

Apparently, for Karai and Leo, it was.

Raphael didn't know what Karai had in mind, but he was rather pessimistic. She would put Leo in danger - not because she wanted to harm him, but rather because it was her definition of having fun.

With a frustrated groan, he jumped the turnstiles at the entrance of the lair. Hopefully it wasn't too late to catch up with them.

He wasn't even ten feet in the sewers when he realized that he had neglected a crucial point. Where was he supposed to go? Neither Leo nor Karai were in sight, which wasn't surprising as they were both experts in stealth.

It still got on his nerves.

Raphael tried to remember what Karai had said. She needed Leo's help for an emergency of some kind… She had also talked about an armory. Where were the Foot headquarters these days? Had Karai returned to Shredder's former lair?

The turtle shivered at that thought. If Karai brought Leo to that place, she wouldn't be able to hide Shredder's absence from him. Leo was going to be suspicious, and what would she tell him?

Hopefully not the truth. Raphael tried to convince himself that Karai wasn't that stupid.

Unluckily, he had no better idea. With a deep cleansing breath - they just wait until he got hold of them - he decided to start there.

When he arrived at the wretched building that Shredder had chosen for himself and his army, Raphael observed with the greatest relief that it was deserted. No Foot, no armory, no Karai and definitely no Leo.

Raphael was back to the beginning.

He decided to look at the problem from another angle. Why did Karay need help?

Maybe the friends he had made in the mutant community could help him answer this question.

* * *

Leo was following Karai, not believing his luck. He didn't know how and he didn't know why, but he had the opportunity to go on a mission with the kunoichi that he… really liked.

It was a comforting thought to know that in the future, she was going to turn away from her father, Shredder, to join them. He was eager to see it happen in his present.

In the meantime, he intended to make the most of this outing.

Karai turned to smile at him. "We're almost there."

He nodded and grinned at his partner-in-crime.

One minute later, she stopped in front of a shop that didn't look much. She pushed the door and entered it.

Leo only hesitated for a second before following her. It would have made a perfect trap, but Raphael had told him that she was her ally, and he trusted his brother.

To Leo's amazement, the backroom was filled to the brim with weapons of all kinds, including katana. He took one on a shelf and watched it closely before whistling his appreciation. It was beautiful craftsmanship.

Karai watched him with a very self-satisfied expression. "Go on, choose what you want."

Leo grimaced and put the katana back on its shelf. "I can't. I'm not a thief."

Karai crossed her arms behind her head as she leaned against the wall. "Who says it's stealing? Everything you see there is mine."

Leo gaped. "Seriously?"

Karai nodded. "I had an inheritance. From a… distant relative."

Leo nibbled his lip. "In that case…"

Having made his decision, he took the katana he had just examined along with its twin, and tied both to his back.

"And now, are you going to tell me where we're going?"

Karai didn't answer immediately. Leo followed her out of the shop and on the rooftops.

"I have to retrieve an artefact. Shini…" Karai noticed Leo's curious glance and shrugged. "She's a friend. She should have come with me, but she had to go to Japan in emergency."

"Retrieve an artefact?" Leo stopped dead in his tracks and crossed his arms. "Now that's stealing."

Karai shook her head. "This artefact is mine by right. It was stolen from the Foot decades ago, and I've managed to track it down. Tonight, it's in New York City for a special conference on Japanese armors. It's a unique opportunity." She pointed at a skyscraper a few blocks away from them.

Leo tried to guess whether she was telling the truth, but Karai's expression was blank.

"Why do you want to get it back? To challenge Shredder? Karai, it's way too dangerous! What are you going to do if he realizes what you've done?"

He didn't understand the half-amused and half-sad look Karai gave him.

"Don't worry about Shredder." She shrugged. "If you're afraid to come with me, you can still keep watch."

Her tone was so disappointed that Leo couldn't help feeling ashamed. Nevertheless, he had a few reservations about this particular mission, as well as a whole lot of questions.

Karai didn't give him time to ask them.

"Maybe Raphael was right. Maybe I shouldn't have taken you with me, you're too young. Your future self would have understood. We've done so many things together…"

She glanced at Leo, waiting for his reaction.

It didn't take long. Leo had no idea about what he and Karai had done - or would do? The situation was beginning to give him a headache - together, but he wasn't going to ditch her. It was a matter of honor. It would always be time to prevent her from doing something stupid later.

Maybe Leo would have been more suspicious if he had known that his adventures with Karai involved blowing up chemical factories and feeding bonfires with bills, but in his blissful ignorance, he nodded with determination.

"Let's go."

* * *

_Past_

In the center of the familial dojo, four turtles were standing in front of a giant rat. Three of these turtles glanced regularly at the fourth, who was pretending not to notice.

Master Splinter had decided to go on with his usual schedule, and therefore his four sons were going to train together.

Leonardo couldn't help feeling tense. He wanted his father to be proud of the ninja he had become, so much that it was almost painful. At the same time, demonstrating his talents was going to involve bring his brothers down in no time, which wouldn't be a very interesting training for them - not to mention the egos he would bruise in the process.

Especially Raph's, in fact.

Splinter gave the signal for the beginning of their warm-up. It was a series of postures to do to the rhythm of their choosing. Leonardo closed his eyes, focusing on the slow rhythm he liked best. He could feel his father's attentive gaze upon him.

He had missed it.

He opened his eyes to Raph's mocking attitude.

"Always the slow one, I see."

Leonardo narrowed his eyes and felt his resolution not to bruise any egos melt like snow under the sun.

As it happened, Splinter was announcing the next exercise. "You'll fight one-to-one. Donatello and Michelangelo first, then Leonardo and Raphael. Take your weapons."

"Hai, Sensei," the four turtles chorused.

As he went to the place where his old katana were waiting to be picked, Leonardo felt a twinge in his heart. He took them and weighted them up, playing with the edge of the swords. They felt so familiar, and still they belonged to a bygone era of his life.

He tried to pay attention to the fight between Mikey and Donnie - Mikey won after an honorable resistance from Donnie - but he was more focused on his future fight with Raph. At that time in his life, his brother had never lost against him. Leonardo would have to take it slow.

Of course, he could always let Raph win. But it wouldn't be honorable - and if Leonardo was entirely honest, it wouldn't be satisfying either.

Raph was already standing up and smirking, certain that he was going to win. Leonardo almost rolled his eyes. Raph really could have been more suspicious. After all, he had no way of knowing Leonardo's current level of skill. Loosing must really be unconceivable for him.

Leonardo stood up and bowed to his opponent, who bowed back.

"Hajime!" Splinter shouted.

And the fight began.

Raph was always 100% invested in his fights, Leonardo had to give him that. His brother was as focused as he was. However, Leonardo had more years of training and real-fight experience, and it became quickly obvious that the fight was unbalanced, even when Leonardo wasn't as offensive as he could have been.

Even Raph realized it. Leonardo saw the incredulity on his face, and decided to end the fight before it could become anger. He adroitly tripped his brother at the same time he was tilting his weapons to make Raph let go of his sai. As a result, Raph fell to the ground.

Leonardo bowed in front of his father, keeping a vigilant eye for the defeated turtle. He knew all too well how good Raph could impersonate a tank.

"Yame! Excellent work, Leonardo." Splinter nodded. "As you can see," he added for his other sons' benefit, "experience is an invaluable asset in a fight."

In his corner of the dojo, Raph was picking himself up, murder in his eyes. Leonardo was preparing himself to avoid his charge when a piercing sound interrupted the red-masked turtle's vengeful trance.

The sound was coming from Donnie's laboratory. Donnie hurried out of the dojo after an apologizing glance at Splinter and came back a few seconds later with the Kraang communication orb.

"I've received a signal!" Donnie was beaming. " The Kraang are gathering around a factory, we have to check what they're doing!"

Leonardo frowned and searched his memory for this particular mission. He found nothing.

Mikey swirled his nunchaku with a grin. "The factory that is the factory that Kraang wants must be protected by the turtles that are the turtles that Kraang wants too," he said with a mechanical voice mimicking the aliens' one.

Raph didn't say anything and picked his sai with a closed expression.

Leonardo stifled a sigh of relief. This emergency came along at just the right time. It was undoubtedly best that his brother take his frustration out on robots.

Leonardo almost pitied said robots.

"Be careful, my sons." Splinter sighed discreetly.

Leonardo's brothers, including Raph, turned towards him. Leonardo realized that they were going to follow him without a second thought, even if he wasn't technically their Leo. It was strangely comforting.

On the other hand, he couldn't help worrying. He remembered all too well what their missions looked like at the time - Mikey triggering every alarm in his path, Raph ploughing into everything that moved, Donnie getting distracted by shiny alien gadgets… and he, Leonardo, who was more or less coordinating them.

When he wasn't falling for Karai, that was.

_Come on, you were managing it four years ago,_ he chided himself. _Of course you can still do it._


	6. Irruption

**Irruption**

* * *

_Present_

Leonardo tried to ignore the little voice inside his head, the one telling him that what he was doing was a really, really bad idea.

It was becoming harder and harder as he followed Karai on the rooftops, then through a chimney and inside a tall building, and finally at the entrance of a wide room full of red lights blinking threateningly.

Inside the room, an ancient-looking helmet lay on a cushion under bulletproof glass.

What had he gotten himself into?

"Karai, are you sure you know what you're doing?" he whispered.

Karai gave him a mocking smile, which wasn't exactly reassuring.

"Don't tell me that a few alarms scare you. You're a ninja, right? But if you don't believe you can avoid them, stay right where you are."

She tilted her head, waiting for Leo's reaction.

The turtle watched the cameras and the probable motion sensors, trying to determine whether or not there was a safe access to the display case.

Karai didn't let him finish his examination and jumped inside the room. Leo admired her agility and grace. Taking his decision, he hurried after her.

In spite of his worries, they both reached the bulletproof glass without problem.

"Watch and learn," Karai whispered, taking a knife from one of her pockets. She began cutting through the glass with it.

"Not bad," Leo admitted. "Where did you find it?"

"It's Kraang technology."

"Are we talking about the Kraang who are trying to invade Earth?"

"Who _were_ trying, you mean," Karai answered, focused on her task.

Leo did as if he was conversing for form. "They don't anymore?"

Karai shrugged. "No, not anymore."

"Do you mean that we won?" Leo smiled from ear to ear.

"If Raphael is asking, I didn't tell you anything." Karai achieved her task and put a small disk of glass on the ground. She put her arm inside the aperture she had just made and opened the display case.

"Here we go!" she exclaimed, reaching for the helmet.

Leo was way less enthusiastic. He was going to reply when a premonition pushed him to unsheathe his weapons.

They weren't alone.

"Look who's there," an unknown voice exclaimed.

In the red lighting, he discerned a shadow looking vaguely like a tiger - a mutant tiger. The tiger was pointing a gun at them, leaving no doubt about his intentions.

"Who's that?" he whispered to Karai.

The kunoichi grimaced. "Leo, meet Tiger Claw."

"He's a tiger."

"Yes, I know. It's in his name."

"He has a gun."

"I can see that."

"Not that I want to repeat myself, but are you sure that you know what you're doing?"

"Of course I do."

It didn't sound very convincing.

"Karai," Tiger Claw said. "I'm not surprised to see you there. Now if you could give me that helmet…"

"He's mine by right," Karai protested.

"The Foot clan deserves better than a child like you." Tiger Claw waved his gun. "And his Japanese branch is paying me very handsomely for this artefact. They would have preferred Shredder's helmet, of course, but as it has become impossible…"

Leo frowned. He didn't understand why this Tiger Claw was talking about the Foot as if they were at war within themselves. Shredder ruled over his troops with an iron hand.

The tiger tilted his head Leo's way, his eyes never leaving Karai. Still, Leo noticed that Tiger Claw's gun seemed to point at him rather than at Karai. Was he supposed to know the mutant?

"I'm more surprised that he agreed to go with you. Is the Hamato clan once more interested by dominance over the Foot clan?"

Leo frowned.

"My father doesn't care about that sort of power," he protested.

He felt Karai tense at her side. Meanwhile, the tiger threw his head backwards, obviously surprised.

"Why are you mentioning the rat? It's not like he could…"

Leo never knew what the end of the sentence was, because Karai moved forwards and Tiger Claw fired.

* * *

Leo had never seen such shots. It was like the gun was loaded with ice and could freeze everything it touched. He did his best to avoid being hit; it would have been difficult in the shadows that surrounded them just a moment before, but Tiger Claw had triggered the alarms, and they were granted flashes of bright light every second or so.

The shrill sirens in his ears were clearly less practical.

Leo waved at Karai to indicate that he was going to distract the tiger so she could leave the room with the helmet. If they were lucky, Tiger Claw would follow her and he, Leo, could then leave the room too. He had thrown shuriken on the cameras, but he didn't want to stay there more than what was strictly necessary. Security services were bound to arrive soon.

Karai nodded discreetly and Leo carried out his plan.

"Tiger Claw! How have you been since last time?"

He was bluffing, of course. He had no memory of the tiger. However, his intuition told him that his future self had been at odds with him.

For a brief second, Leo was happy to be right. His happiness faded when he had to redouble his efforts in order to avoid the tiger's gun. From the corner of his eye, he saw Karai semi-circling around Tiger Claw to leave the room.

"You're different. Your voice…"

Leo wasn't pleased with the tiger's suspicious tone. He was missing key information to understand what was wrong with his voice, or to what extend he and Tiger Claw were on bad terms.

Tiger Claw had come close enough from him to see him clearly, and Leo glimpsed a flash of understanding in his eyes.

"It can't be," the tiger whispered. "You look so much younger. What happened?"

"It's a long story," Leo said.

In a lightning-fast move, the tiger sheathed his gun to take a long sword. Leo gritted his teeth, focusing on the close combat that would follow…

Half a second later, he was pinned to the display case by a furry paw, the tip of a sword tickling his throat and his katana meters away from him.

The tiger gave him an evil smile. "It's a shame you didn't keep your reflexes, isn't it? You know, I've been wondering what I would do if you were at my mercy…"

"I'm sure we can talk this out," Leo answered, feeling around in his back in the hope of finding something useful.

"Alas, I'm not in the mood for discussion." The tiger sighed ostensibly. "I don't want Karai to escape with my prize. I'm sure you'll understand."

Karai was standing at the door, having apparently realized that Leo needed help. Tiger Claw sheathed his sword and took his gun, firing multiple times to dissuade her from interfering. He began pressing against Leo's throat with his other arm.

Leo tried to break the tiger's hold, but Tiger Claw was stronger than him. The turtle gasped for air.

His vision was getting blurred, but he nonetheless recognized the green and red shape that jumped down Tiger Claw's throat with his sai out.

"LET HIM GO!"

* * *

Raphael had just had the fright of his life.

Or at the very least, one of the frights of his life.

He had gone to Slash, his former pet turtle that he used to feed on salad and who was now twice his size and four times his weight, to know whether he had any idea of what Karai was up to. Slash had told him about the rumors he had heard - that Tiger Claw was back in town - and had guided him to the last place the tiger had been seen. Slash's team, comprised of the telepath genius Doctor Rockwell, the powerful Leatherhead and the fanciful Mondo Gecko, had come with them.

They were close by when they heard the sirens, and Raph had immediately known that Leo was in trouble.

Raphael's four allies had stayed behind to slow down the guards while he stormed on the floors. He had arrived just in time to see Tiger Claw try to strangle his brother.

His beloved stupid brother. Nobody lay hands on his family without suffering the consequences. Nobody.

Especially not since Splinter…

Raphael blocked that thought and glanced at Leo to make sure his brother was alright - Leo was coughing and stroking his throat but he didn't seem injured - before focusing again on his current goal: to turn the tiger to dust.

Said tiger wasn't exactly cooperative, but Raphael couldn't have cared less. He was mad with rage and relief, which made him especially dangerous.

"Raphael, that's enough," said a voice.

Raphael recognized Karai. She had managed to take Tiger Claw's gun and was pointing it at his opponent.

However, he wasn't going to comply. He was on the verge of tearing off Tiger Claw's tail stump. Besides, he was holding Karai responsible for that near-disastrous situation, and he didn't feel like talking to her.

"Raph," another, hoarser, voice said.

Raphael was willing to answer that voice.

"I'm busy, Leo," he groaned.

"Raph, we really have to go. The alarms…"

"Don't worry about it. We've friends taking care of the guards."

"Raph!" Leo insisted.

While they were talking, Tiger Claw made an attempt at a particularly vicious attack and almost managed to get hold of Leo. Raphael decided that it was time to let Karai's gun do its job and threw himself backwards - with regret.

Karai used the gun to imprison Tiger Claw in a prison of ice. Raphael had no doubt that Tiger Claw would free himself, but not before they had all left the place.

"Thanks for your help," she told him.

Raphael ignored her the same way he ignored her goodbye to Leo and her threats to Tiger Claw - a confusing story involving a helmet - and followed Leo out of the room. He restrained himself from shouting at his brother when he realized how frequently Leo was glancing backwards.

In the lobby, an epic scene was waiting for him. Slash and his team had made a pile with the unconscious bodies of the guards, and Mondo Gecko was trying to use it as a launching ramp for his skateboard tricks.

Leo gaped.

"Leo, meet Spi… Slash and Mondo Gecko. You already know Leatherhead and Rockwell," Raphael mumbled.

"I… Hello," Leo managed to say.

"Greetings, Leonardo." Slash bowed his head and didn't say more. Raphael had told him about the circumstances.

Leo couldn't tear his eyes away from the giant turtle and his mace. He looked stunned.

"Then Mikey was right," he whispered.

"Happens from time to time." Raphael hoped that his grumpy tone conveyed the full extent of his foul mood.

Slash raised his eyebrows. "Is everything alright?"

"Oh, it couldn't be better," Raphael retorted, crossing his arms. "Leo almost got killed, as usual."

Slash coughed. "Well, we're going to leave you. Raphael, it has been a pleasure to help you."

"Thanks," Raphael whispered.

The way home was silent. Leo seemed deep into his thoughts and Raphael had no intent to begin conversation.

_I knew she meant trouble, _he raged per se. _I knew it. But does anybody listen to me? Of course not! It's too much to ask for!_

Leo's voice interrupted his silent diatribe.

"Raph, why do I have the feeling that Karai and this… Tiger Claw… are fighting to take control of the Foot?" he asked softly.

Raphael bit his lip, his anger vanishing. What had his brother heard? What had he deduced? Leo was a born strategist, he was bound to develop theories.

"You're getting the wrong idea, Leo. Karai and Tiger Claw have always hated each other. I guess she just wanted to throw a wrench in his gears."

"He seemed to hate me more than her," Leo mused.

"Yes, well, he might hate you a little too. Nothing personal," Raphael answered awkwardly.

He hoped that Leo wasn't going to try and learn more about that matter, and did his best to hold his brother's piercing gaze.

* * *

Leo felt frustrated. He didn't know much about this future. He recognized neither his enemies nor his allies, and he was obviously not skilled enough to fight someone like Tiger Claw, even though the other Leo must have been able to do it.

Besides, he didn't understand the situation. Why did Karai and Tiger Claw fight for this helmet? And Tiger Claw had talked about the Foot clan, but never mentioned Shredder ruling it. He had implied that Karai wanted to take control of the Foot… Had she lost her mind?

There was only one thing Leo was absolutely certain of: Raphael was hiding something from him, something essential.

And Leo was going to find out what it was.


	7. Tension

**Tension**

* * *

_Past_

Leonardo was getting ready for the mission to come, his gestures outlining years of habit. He was placing his good old katana on his back when he felt a familiar presence behind him.

Mikey was standing on the armory's doorstep. The turtle came closer to Leonardo, grinning.

"We're ready," he said in a conspiratorial tone. "Raph is grumpy, but…" He glanced backwards to check that they were alone. "It was awesome to see him bite the dust for once! I mean, of course Splinter takes care of that from time to time, but he's Splinter, it doesn't count. He's invincible!"

Mikey winked at Leonardo, who did his best to smile and not show how much these words rekindled painful memories. His brother believe that their father was invincible. Leonardo had been firmly convinced of it too, before reality proved him oh so wrong…

Reality, by Shredder's hand. Shredder who was at this precise moment alive somewhere in New York, planning his next move against them…

_You can't interfere. You can't risk changing the past._

"Leo, are you okay?"

Leonardo realized that Mikey was watching him strangely. He gave his brother a forced smile.

"Of course I'm okay. Let's go!"

Leonardo checked one last time that he hadn't forgotten anything and left the armory with Mikey in his wake to join Raph and Donnie.

Splinter told them goodbye right before they jumped the turnstiles. "Be careful, my sons."

"Hai, Sensei," they chorused.

Leonardo turned away quickly and left the lair, a sad smile on his lips.

He had missed these ritual words.

* * *

Guided by Donnie, the four turtles arrived safely in front of the factory where the Kraang were supposed to meet. Indeed, a dozen of droids were aligned in the street, waiting for something or someone.

"There are more of them inside," Donnie whispered, looking at one of his many doohickeys.

Leonardo nodded. "Then let's be especially careful. We're going to enter through…"

His brothers were already gone. Leonardo facepalmed.

"Of course."

He hadn't missed _that_ at all. With a sigh, he followed them through a half-opened window. The factory was huge and plunged into darkness. Leonardo watched its equipment, wondering what was manufactured there. At least it didn't look like a chemical factory. Motors maybe?

He found his three brothers hiding behind a set of machines and glared at them, which they completely ignored.

"What are they up to?" Raph asked, pointing at another group of Kraang ten feet away from them.

These Kraang wore costumes. Half of them were looking at a monitor while the others stood guard.

"If only we knew," Donnie whispered. He leaned forwards, probably in the hope of glancing at the monitor.

Leonardo caught him at the very last moment and pulled him behind the machine. A Kraang was turning around to watch his surroundings.

"We're too exposed," Leonardo whispered. "Let's climb to the ceiling."

His brothers nodded, and soon the four of them were hiding behind the girders. Donnie sneaked close above the monitor to see what was keeping the aliens busy and came back almost immediately, a half-somber and half-excited expression on his face.

"These are blueprints for exoskeletons," he said. "They intend to manufacture exoskeletons!"

Leonardo bit his lip. The Kraang already had robotic bodies, why should they need exoskeletons?

"Very interesting, Donnie, very interesting." Mikey nodded intensely. "And, uh… what's an exoskeleton?"

"Well, it depends," Donnie began with his teacher's voice. "Some animals, like turtles, have an exoskeleton that protects them from predators. It's made out of bone and…"

Raph cracked his knuckles.

"… And in the present case," Donnie went on, wisely shortening his talk to avoid bodily harm, "an exoskeleton is a mechanical super-armor that can increase a human's physical strength."

"But which human?" Leonardo whispered.

"I would like that," Mikey mused. "Having an armor to increase my strength, I mean. I'm sure Raph is cheating. He must already have an exoskeleton!"

Raph puffed himself up, satisfied because his superior strength was being acknowledged. Leonardo smiled inwardly while Donnie raised a finger.

"Yes he does! It's called a shell."

"A second exoskeleton, then," said Mikey who didn't want to give up on his idea.

"Whatever. I suggest that we don't let the Kraang make them!" Raph exclaimed, taking his sai.

Leonardo assessed the situation. "I would like to know what they're waiting for. Let's move away and wait before we interfere."

"Of course, good idea," Mikey said, filled with goodwill. "Let's move away discreetly, before they notice that we're here. Or before someone sets an alarm, like this one." He waved with his nunchucks at a big red button close to them on the wall.

Leonardo merely had the time to open his mouth before said nunchucks hit said button. A shrill siren resonated inside the factory.

"Mikey!" Leonardo and Donnie exclaimed while Raph was grinning in anticipation of the upcoming fight against the Kraang.

Mikey smiled sheepishly at his brothers.

"Oops."

* * *

For the thousandth time, Leonardo wondered how he had managed to find himself in this predicament.

A multitude of Kraang coming out of nowhere - or more precisely, coming from a nearby portal to Dimension X - was pouring inside the factory. Leonardo's anxiety levels were reaching new records while he kept an eye on his three brothers and their enemies, making sure that no improved and too-strong-for-them Kraang arrived.

At least Raph seemed overjoyed.

"Donnie, Mikey, try to find the portal they're coming from and close it," Leonardo ordered. "I'll stay with Raph."

"Roger that," Mikey exclaimed as Donnie nodded.

Raph shook his head while he stabbed droid after droid. "I don't need your help, Leo."

Leonardo rolled his eyes and opted for diplomacy. "I don't doubt it, Raph, but we'll be more efficient together."

And they were efficient indeed. The Kraang weren't causing them problems, they were just very numerous. As soon as Donnie and Mikey had managed to close the portal that allowed the aliens to come inside the factory - a task broken with many a "Mikey, no!" and "Don't touch this!" but which was ultimately a success, like Leonardo had hoped considering Mikey's gift with Kraang portals - Leonardo and Raph quickly finished the droids.

"Look at that. And to say that I was afraid the night would be boring."

Donnie, Mikey and Raph tensed while Leonardo sighed heavily. Obviously they hadn't been fast enough, and the people that the Kraang were waiting for had arrived before they had a chance to hide once more.

"Her again?" Raph grumbled.

"Karai," Donnie mumbled, his tone colder than ice.

For once, Mikey wasn't smiling.

Their half-sister-raised-by-the-murderer-of-her-mother-and-who-still-didn't-know-it stood in the factory's entrance with a group of Foot soldiers armed to the teeth. She smiled, satisfied with their reaction.

It wasn't exactly a welcoming smile, and Leonardo instinctively took a defensive posture. He waved at his brothers to do the same, which they did without protesting.

"Leo, I swear that if you try to negotiate with her…" Raph whispered.

"It's not on my agenda," Leonardo said through gritted teeth.

Karai nonchalantly unsheathed her weapon. "I had come to retrieve blueprints, but fighting turtles is a nice bonus. Until I can have the rat."

Leonardo gripped his swords tighter and forced himself to take deep breathes. He could see more and more Foot ninja sneak inside the factory. His brothers and he were too exposed.

Besides, Karai might very well have reinforcements. Tiger Claw wouldn't be in New York, not so early in his past, but Bradford and Xever would, and Leonardo didn't see them. Unless Shredder had entrusted this mission to Karai only?

In any case, there were too many unknowns.

"We're leaving," he whispered to his brothers. "The windows. On my mark…"

"Are you kidding?" Raph exclaimed. "And what about the exoskeletons' blueprints? Do you really want the Foot to have them?"

_They don't matter, the Foot never used them, _Leonardo wanted to say. _We've had Footbots instead, and believe me, they've made our lives difficult._

Karai waved her hand, and Leonardo heard the unmistakable sound of stretching bows. He swore inwardly.

"That's right," Karai whispered, her smile predatory. "We didn't trust our allies, you see. As you know, my father has a slight tendency to paranoia. Well, anyway…" Her stare became icy. "You wouldn't want to leave before the guest of honor arrives, would you?"

She shifted slightly and bowed towards the door.

Leonardo's blood ran cold. A shadowy figure was entering the factory, a figure that he would have recognized anywhere.

It was Shredder.


	8. Confrontation

**Confrontation**

* * *

_Present_

Leo lay on his bed, thinking about the situation. It was obvious that Raphael and the others were hiding key elements of his future from him. On one side, he could understand it - after all, he was sort of an intruder here. He hadn't shared the same adventures and experiences that they had. On the other hand, he was highly suspicious and intended to discover what was happening.

He missed his father. If only he could have talked to him, he had no doubt that Splinter would have listened and soothed his worries. He had asked his brothers when Splinter would come back, and they had looked at each other with panicked expressions before Donatello answered 'In a few days'.

Leo's intuition told him that his brother was lying, but he hadn't pressed. If his brothers didn't want to tell him what was up, so be it. He would investigate solo.

Leo stood up silently and left his room. His brothers were discussing in the living room. From his observation point in the hallway to the bedrooms, he could hear them perfectly.

Raphael had his arms crossed and was turning his back to him. From his intonation, Leo could tell that he wasn't exactly in a good mood.

"Donnie, about this time travel machine. How is it going?"

Donatello was facing Raphael, and considering the tools in his hands, he was coming straight from his laboratory. Leo guessed that he was very close to throw said tools in Raphael's face.

"You think it's easy?"

Raphael shook his head, irritated. "And Renet who doesn't answer…"

On the couch, Michelangelo was swinging back and forth. "Give her some time, Raph. I've left her several messages, I'm sure she'll call back as soon as she can."

"'Give her some time', easier said than done!" Raphael threw his arms up. "Do you think we have time? Leo has been here for only one day, and he has already managed to find himself in an impossible situation. If I hadn't arrived on time…"

Leo blushed. Deciding that he had heard enough, he sneaked unnoticed through the living room and inside the dojo.

The room was in the exact same state it had been left a few hours ago, when he had trained with Raphael. He hadn't payed much attention to the place then; he had been too focused on the fight against his brother.

It was time to remedy that.

Leo began his examination with the shelf where his father's favorite picture was displayed, then looked at the armory and its weapons - a few of which he had never seen - and even lifted the carpets, just in case.

Nothing unusual.

Leo glanced at the screen marking out the entrance of Splinter's room. He would never have dared to enter that room without his father's explicit permission. With a shrug, he left the dojo.

Inside the living room, Raphael was hitting his punching ball in rhythm while Michelangelo played one of his video games. Donatello was nowhere in sight.

Still on his tiptoes, Leo went to the kitchen to search the cupboards. He didn't find anything special until he opened the freezer - and jumped backwards.

"Meeeeowwwwwwwww!"

The thing inside the freezer - a cat? a giant meowing ice-cream? - watched him with big eyes.

"Ice Cream Kitty!" Michelangelo hurried inside the kitchen. "Leo, be careful, we don't want her to melt!"

"It's… it's your _pet_?"Leo asked weakly.

Michelangelo nodded with pride. "She's my cat, and I'm her turtle," he answered while said cat showed her affection by licking his cheek, leaving a trail of ice-cream.

Michelangelo licked it. "You okay, Leo?"

"I… Yes. Of course." Leo shook his head. "I'm not sure I want to know where she comes from."

"I mutated her on accident. Donnie was so mad, but she helped us a lot!"

Leo inhaled sharply. "A baby mutant turtle alien. An ice-cream cat. Is that all, or do we have a mutant dog in the trash can?"

"No, that's all, Leo." Michelangelo grinned at him.

Leo nodded once before leaving the room with the beginnings of a headache. He decided to take shelter in his room to recover from his emotions.

He sighed as he closed the door behind him. He was back to the beginning. Where else could he look for clues?

He was absent-mindedly letting his eye wander over his room when the obvious struck. Of course! His own belongings might help him understand what was going on!

His enthusiasm renewed, Leo began searching.

Oh, apparently he had kept reading strategy books. And his precious comic books were still there…

A package in the back of his closet drew his attention. It was oblong and covered with a black cloth. Frowning, Leo hesitated for a second before taking it and removing the cloth.

He stayed motionless in front of the objects just revealed to his sight. Objects he knew like the back of his hands, objects that he would never have left in this state…

Raphael had indeed lied to him. His katana weren't with his future self, they were there, in this future.

Broken.

* * *

_Past_

Leonardo felt oddly calm as he watched the leader of the Foot clan enter the room. A part of him was conscious of every sound, of every move - his brothers muffled exclamations, Karai's smirk, the whistling of Shredder's gauntlets ripping through the air - while the other was reliving his past… the future… on the rooftop of a burning mansion, breathing the choking fumes of the fire, flames dancing in the background…

The night when he had fought both his father's brother and his father's murderer. The night when he had killed him.

"I didn't expect to see you there, turtles," spat the very alive man in front of him, "but this is an opportunity I won't pass. Tonight I'll have my revenge. Tonight you'll lead me to Hamato Yoshi!"

Shredder jumped forwards, obviously aiming to defeat them once and for all - and after all, he only needed one turtle alive to guide him to his enemy's lair…

Leonardo blocked his attack.

All those present froze, from his brothers to Karai including the last of the Foot.

"What?" Shredder watched Leonardo in sheer incredulity.

Leonardo guessed more than he saw Shredder's next move, and shifted to block him once more.

"Impossible," his opponent whispered. "I've seen you fight. You're not… You can't…"

With a roar, he jumped down Leonardo's throat. His attacks were ferocious and merciless. He was a hardened fighter, a master of ninjitsu…

And so was Leonardo.

His determination was every bit as good as Shredder's. The man would not hurt his family. Leonardo would do everything it took to prevent that from happening, and he had proved it…

Attacks and parries came one after the other, Leonardo's katana slicing through the air with millimetric precision under his brothers' still shell-shocked gaze.

Leonardo frowned. "Move!" he yelled, breaking the spell.

Raph, Donnie and Mikey began fighting the Foot around them while Karai stayed on the side to watch the duel. The archers tried to fire at them, but they didn't dare throwing arrows too close to their leader. Mikey hastened to disarm them one after the other.

Leonardo was focusing on his own fight. Shredder was frustrated and began to make mistakes. Soon Leonardo would have an opening. Soon…

Now.

In one fluid move, Leonardo sent Shredder's helmet flying. The man was at his mercy, his unprotected head within an inch from the very sharp edge of Leonardo's swords... One gesture on his part and Shredder would become a memory unable to cause Splinter's death…

Before he could take his decision, though, Karai jumped on him. Leonardo easily pushed her back, but the moment was gone.

Leonardo had come to his senses. Shredder's death in that time, in that place, would have repercussions that he couldn't anticipate on the future and on space-time itself. It would be madness.

Gritting his teeth, Leonardo used the handle of one sword to knock the Foot leader out.

"What the… Who _are_ you?" Karai whispered as she picked herself up.

Leonardo didn't answer while she scrutinized him. He had never been more aware of the marks that time and countless fights had left on his body. There was that missing part of his shell, and the scars on his throat and arms…

"Leo?"

Raph's trembling voice brought him back to reality. His brothers had managed to knock down most of the Foot soldiers. Those who were still standing, shocked, were no immediate danger.

"We'll meet again, Karai," he whispered to the kunoichi.

Turning to Raph, Donnie and Mikey, he took one of the ninja smoke bombs invented by the genius of their team.

"Let's go!"

Half a second later, he and his brothers disappeared into the night.


	9. Explication

**Explication**

* * *

_Present_

Leo remained prostrate, unable to look away from his weapons. He slid his fingers on the flat of the broken blades.

What had happened? Why were his katana - weapons he took extreme care of - in such a state?

He needed answers, now. Picking the pieces of steel, he stomped out of his room, all stealth forgotten.

Raphael and Michelangelo were still in the living room. Leo stood in front of Raphael and let go of the blades, which fell to the floor with a thunderous noise. Donatello, alerted by the racket, ran out of his lab.

"They were with me, right?" Leo said bitterly.

He didn't miss how Raphael's face was distorted by panic and regret - and was it pain?

"No, Leo… It's not what you think…"

"Not what I think?" Leo almost shouted. He crossed his arms, doing his best to keep calm and not yell his frustration at his brothers. "You think I don't know my own weapons?"

It was obvious that Raphael would have preferred to be anywhere but here. The blamed turtle gave Michelangelo and Donatello a desperate look. Michelangelo jumped behind Donatello while the tallest of the turtles twisted his hands.

"Leo… I think it's better if you don't try to learn anything else…" he tried.

Leo watched him with incredulity. "And you're the one saying this?"

Donatello cleared his throat. "I just wanted to say that… that…" He put his hands behind his back, thinking fast. He needed an idea. What could he come up with? Lying was harder than building machines, but he didn't have a choice. He couldn't tell Leo the truth.

_What can break katana? _Donatello thought.

He suddenly had an illumination. Sai, of course!

Giving Raphael an apologizing glance in advance, Donatello went on. "Raph broke them. You fought each other with more intensity than usual, and, uh… You haven't had time to repair them yet."

Raphael gaped and threw daggers at Donatello.

Leo watched each of them in turn. He lifted an eye ridge. "You really think I'm going to buy this?"

Donatello shrugged. "It was worth a try," he mumbled.

"I think it was an awesome idea, Donnie!" said Michelangelo, still hiding behind his brother.

Raphael still looked like he was going to turn Donatello into a sieve with the sheer power of his glare. Donatello made sure that the couch remained between he and his brother at all times.

Leo ignored them, too busy thinking. What were his brothers hiding from him? It had to be something dramatic.

He thought about his weapons. He had found them wrapped in a black cloth. True, it was a color appreciated by ninja - but it was also a color of mourning.

Could it be…?

With a sudden lump in his throat, Leo expressed the thought that had just dawned on him.

"Something happened to me, didn't it?"

* * *

_Past_

Neither Donnie, nor Raph, nor Mikey made the slightest comment on their way home. Donnie merely mentioned that he had managed to erase the exoskeletons' blueprints with a computer virus. Leonardo had congratulated him, and Donnie had accepted the praise with a shy smile.

Since then, nothing.

As they jumped the turnstiles of their home, Splinter left the dojo to meet them. Leonardo took a deep breath. How was he going to explain to his father what had happened? He had a hard time believing it himself.

He had defeated Shredder… For the second time.

The leader of the Foot was bound to give them no respite. He was going to want not only Splinter's head, but Leonardo's too. What if his past self came back? He was no match for Shredder and wouldn't be for a long time. He would be killed…

_What have I done?_

"Did everything go well, my sons?"

Splinter's question broke the spell of silence.

"Oooh, you could say that! What a fight!" Raph came closer to Leonardo and patted his shoulder. "Not bad, not bad at all!"

Raph's tone was admittedly a little strangled, but it was also warm and welcoming, and Leonardo gave him a pale smile.

"Who would have guessed?" Donnie said dreamily. "Our future is decidedly full of surprises…"

"Master Splinter, it was incredible!" Mikey exclaimed. "First there were all these Kraang - and Donnie and I destroyed their portal, and Raph and Leo busted up those left, and then Karai arrived! With archers, lots and lots of archers!" Michelangelo extended his arms to show how many archers there had been. "And then Shredder joined her, and…"

"What?" Splinter yelled.

His raised voice shut Mikey up for a whole second.

"And then Leo defeated him," he finished in a whisper.

In the heavy silence that followed, Leonardo did his best to hold his father's gaze. He couldn't decipher the emotions mixed up in it. Surprise? Concern? Incredulity?

"I… It just happened…" he whispered.

"Oh, my son, what have you done?" Splinter sighed. "Come with me. I want you to tell me everything down to the last detail."

* * *

_Present_

Michelangelo was the quickest to react. "Something happened to… what? Oh, Leo, no! Not to you!" he said spontaneously before covering his mouth with his hands in horror.

Raphael and Donatello glared daggers at him.

"Of course nothing happened to you, come on, Leo," Donatello hurried to say. "I mean, apart from the fact that you've disappeared somewhere in the corridors of time."

Leo scrutinized him. This time, he had a feeling Donatello wasn't lying. And now that he was thinking about it, it was stupid. His brothers had been surprised to see him, granted, but not upset like they would have been if Leo hadn't been part of their lives anymore.

Then what?

Michelangelo's words echoed in his head.

_Not to you. Not to you. Not to you._

To whom?

Who wasn't there, and should have been? Who was supposed to have left in order to train April, when he could have done it in the dojo?

"No," Leo whispered.

He watched each of his brothers in turn. Raphael froze when he saw Leo's expression. Donatello clenched his fists. And Michelangelo… Leo could read in his eyes such a grief, a sorrow that should never have belonged there, and it was the only confirmation he needed.

His world collapsed.

"Nooooooooooo!"

* * *

_Past_

Leonardo was following his father and brothers to the dojo when the pain overwhelmed him. It was like his whole body was hurting, like each and every one of his cells was crying its grief…

"Leonardo?"

Splinter's voice sounded very, very far away as Leonardo tried to breathe. Deep inside him, he knew what had happened. This devastating sorrow was nothing new to him… Somewhere, some time, a Leo way younger than him had learned the terrible truth. A truth that he was unequipped to meet.

That truth had almost broken Leonardo himself, and he had been much more hardened than his past self at the time…

"Leonardo!"

He felt Splinter's arms wrap around his shoulders to support him.

"I'm okay," he managed to say. "I'm okay."

"What happened, my son?"

Leonardo felt himself unable to hold back his tears.

"He knows," he whispered, more to himself than to his father or his brothers. "Father, I'm so sorry…"

He choked and hid his head in Splinter's robe.

"So, so sorry…"

* * *

_Beyond Time_

"The Time Scepter has a mind of its own." Lord Simultaneous pensively watched the various monitors in the room. Eight turtles, one rat and one absolutely furious armored human were displayed in high definition. "Still, you've once more demonstrated your carelessness."

Renet wished she could disappear inside a tiny, tiny hole. When she had finally listened to Michelangelo's pressing messages, she had hurried to the Time Scepter room only to discover that it was gone. Lord Simultaneous had taken it with him, and she had been forced to wait for his return.

And to tell him everything.

His master's stare pierced her.

"Go and fix this."


	10. Resolution

**Resolution**

* * *

_Present_

"Leo!"

Leo had fallen to his knees and held his head in his hands. He wanted to disappear from this future, a future that should never have existed.

He felt familiar hands press his shoulders.

"I'm sorry, Leo," Raphael's voice whispered. "I tried to…" He shut up, tightening his grip on his brother.

Leo raised his head to look him in the eye.

"How did it happen?" Uttering these words was a torture, but he needed to know. "Why didn't we save him?"

"We couldn't." Raphael closed his eyes. "You weren't even around, you…" He realized too late that it wasn't exactly the right thing to say.

"I wasn't there?" Leo wiped his eyes angrily. "I should have! I should have, and…"

A blinding white light cut him off. A second later, a particularly embarrassed Renet cleared her throat.

"Uh, guys? Sorry I'm late, I, uh… I've come for Leo."

Raphael jumped on his feet and walked over her with his fists raised. "Oh, so _now_ you're coming?" he yelled, seizing the opportunity to release some of his frustration.

Michelangelo and Donatello caught him by the arms and held him back.

"Sorry, sorry, I'm really sorry," Renet whispered. "I'll sort this out immediately." She came closer to Leo and put a hand on his shoulder.

"I really don't see how," Raphael said bitterly.

Renet bit her lip. "He won't remember. I… See you soon."

Raphael turned his head away while she disappeared with Leo. Maybe Leo wouldn't remember what he had discovered - good for him - but he, Raphael, wasn't going to forget the pain on Leo's face any time soon.

"I really hope it went better for our Leo," Michelangelo whispered.

* * *

_Past_

"Leonardo? My son, you're worrying us," Splinter said softly. "What's the matter?"

Leonardo teared himself from his father's embrace. He had wanted to lay low until Renet and his brothers brought him back to his own present.

It had backfired. But what could he say? How could he repair the damage he had done? Was it even possible?

Leonardo glanced at Raph, Donnie and Mikey, packed together as if they could feel his pain.

The arrival of two people in a flash of blinding light dispensed him from finding an answer.

"Hi everyone," Renet trumpeted.

Leonardo watched her in incredulity before turning his attention to the second figure, a turtle that looked a lot like him - although he seemed in a worse condition than him. He shifted to allow said turtle to take his place in Splinter's arms.

Splinter lowered his ears, a sign of strong emotion. It was the second time in less than five minutes that he had to comfort the same son. He must really be wondering what was happening - unless he had guessed it, which was even worse.

"Hi Renet," Leonardo said, his hoarse voice not especially welcoming.

"I'm sorry, who am I speaking to?" a baffled Donnie interjected.

Renet bowed to him. "My name is Renet. I'm sorry about this rude interruption. We'll meet again later. Much later."

Donnie threw his arms up. "That's all? Excuse me, but I would really appreciate to understand what's happening here!"

Renet shook her head. "No time. This timeline has already been too altered, the Time Scepter has barely the energy required to sort things out."

She caught Leonardo's skeptical look and smiled at him.

"Don't worry. Nobody here will remember a thing." She patted the Time Scepter. "I've checked the settings."

Both Donnie and Raph crossed their arms. As for Mikey, he seemed unable to look away from Renet.

Renet sighed. "Erm… My apologies again. Leo, we go?"

Leonardo took a deep breath. It was more than time for him to return to the future, his present.

"We go."

Splinter hugged Leo even more tightly as he gave Leonardo a sad smile.

"Take good care of your brothers," he whispered.

Leonardo bowed low to him before taking Renet's hand.

He would be happy to see Donatello, Michelangelo and Raphael again. He missed them.

* * *

_Present_

Raphael's relief was immeasurable when Leonardo and Renet reappeared in front of them, a few seconds only after the apprentice Time Mistress had left with Leo.

Leonardo seemed shaken, and Raphael lost no time in taking him in his arms in what could only be called a bear hug.

It went without saying that Donatello and Michelangelo hurried to help him with this important task.

Leonardo accepted his brothers' hug with gratitude and didn't break apart from them until he began running out of air.

Renet watched them with a tender and more than a little guilty expression.

"I'm happy to tell you that everything is back to normal in your past. My apologies for the inconvenience."

Raphael glared at her, but Leonardo merely nodded.

"Thanks, Renet. I'm relieved that my past self won't remember anything."

Renet gave him an awkward smile.

"And now I'm going to leave you. I've an appointment with dust in the Time Library…" She sighed.

While Michelangelo said his goodbyes to her, Raphael dragged Leonardo to the couch.

"And now you tell us everything."

* * *

"And that's when Renet arrived."

Having finished his tale, Leonardo took another sip of the hot tea Donatello had made for him.

Michelangelo, who was nestled against him on the couch, whistled. "Okay, well, you've really been busy there too."

Leonardo lifted his eye ridges. "What do you mean, _too_? What happened here?" He felt a lump in his throat. "Apart from the fact that my younger self learned the truth."

Michelangelo squeezed up tighter against him.

"Oh, nothing out of the ordinary," Raphael said half in earnest, half in jest. "After all, you've only managed to give me the slip, to steal an artefact with Karai _and_ to almost get killed by Tiger Claw."

Leonardo abruptly straightened up. "Tiger Claw is in town?"

"Yes he is," Donatello said. "I've compared our information with Rockwell's. We can fill you in later."

Leonardo nodded. "As soon as you've told me your part of the story."

Much later that day, Leonardo sat under the dojo tree. Michelangelo had put Splinter's shrine back in its place, and Leonardo had burned incense sticks on it.

He was pensively looking at his old katana. His brothers had told him what had happened with the young Leo.

He felt Raphael come inside and sit down next to him.

"Are you going to repair them?"

Leonardo hesitated. He hadn't wanted to at the time. These weapons were a symbol of his lost past and he had wished a clean cut.

"Maybe someday."

Raphael nodded. "Alright. I could help you with it, if you want," he offered almost shyly.

Leonardo smiled at him. "I would like that."

Raphael smiled back. "That way, they won't betray us if Renet strikes again," he joked to hide his melancholy.

Leonardo shook his head. "I don't think we'll be seeing here again for quite some time. Lord Simultaneous will probably want to keep her busy after what happened, and…"

A clear voice echoed from the living room. "Good news, guys! I'm done! Phew, I thought these three months were never going to end!"

Leonardo and Raphael exchanged a long look.

"I think I'm going to keep meditating in this dojo for a while," Leonardo said.

Raphael patted his shoulder. "Excellent idea."

* * *

**Epilogue**

* * *

_Past_

Shredder sat on his throne, his daughter kneeling at his feet.

"Father? Will you come with us?"

Shredder hesitated. He didn't know why - nothing unusual had happened lately - but he didn't feel like going out. There was this feeling, deep inside him. He didn't quite know what it was… Fear, maybe?

The Foot clan leader shook himself. He was being ridiculous. Nothing and nobody made an impression on him.

Nevertheless…

"No, Karai. You'll be responsible for this mission."

He watched as her daughter stood up, bowed to him and left the room. He had raised her well, she would stand her ground.

He felt safer in his fortress.

* * *

_Author's Note: For the record, I've often wondered why Shredder wasn't more involved in the fight against the turtles. It's partly what inspired this story. Thanks to everybody who showed an interest in it!_


End file.
